Pulsacoil 2000 Intermittent Problems

Hi,

I moved to a property which has a pulsacoil 2000 installed. Initially I faced a lot of problems with this but the landlord sent his contractor who went through everything and over time replaced the following:

1. Relay (initially incorrectly installed but he corrected that later)
2. Fuse on the off peak power switch
3. Sensors and sensor wires

After all this, it has been working properly but once a week I do not get hot water early in the morning despite the off peak heating running throughout the night. When I open the tap, the water initially comes hot implying that the water is heated (which I have also checked as the heater itself feels hot) and most of the days it stabilizes to normal hot water as expected from the pulsacoil but once every week (sometimes once in 10-12 days) it goes to cold from the initial hot and then remains so.

If I then wait and run the tap a couple of hours later, it works fine and remains so for the whole day additionally confirming that the water did heat in the night.

It will be great if someone can advise where this problem could lie? Is it due to the thermostat which is not recording the correct temperature of the incoming water off and on or something else.

Thanks a lot for the help.

Pc 2000.
Could be sensor, there are 2.
DHW pump.
Pump drive PCB.
That is it.
I take it the unit is full. Top tank checked!
Mike
MGC/H2O
Norwich
Norfolk

Thanks Mike.

Sorry should have mentioned that had checked the top tank and that was full. Sensors were recently replaced so most prob that is not the problem in this case.

The landlord's contractor came by and the boiler was working properly at that time with even the light blinking properly 2 times a second as opposed to the 7-8 times per second in the morning. He checked the pump and that was working. Is there an easy way to check the Pcb to see if that has an issue except by replacing it?

Thanks a lot.

Hi,

My landlord's contractor came by and replaced the heat exchanger and the pump but we are still not getting hot water at the taps.

1. The pump is hot to touch
2. So is the heating element

This indicates to me that the water did heat overnight but it is not being pumped through to the taps when hot water tap is opened.

The PCB LED blinks two times a second but when the hot water tap is opened, it sometimes blinks 7-8 times a second and sometimes 1 per second indicating that both the thermistors might not be working though this seems strange as the contractor had replaced both of them in the near past when the problems initially started and he has replaced the pump and the heat exchanger now as well.

Can you advise how can I check using an induction current detector whether the current is flowing through the relevant wires where expected? As in what all points do I need to check with the hot water taps on and the hot water taps closed.

Also, any other suggestions to what might the issue be?

I live in the Isle of Dogs area in London, so any pointers to good local repairmen would help as well in case the landlord's contractor is still not able to fix it.

Thanks a lot for the help.

PC 2000;
Sensors are the wires connected correctly.
When a hot tap is turned on is there voltage at the pump?
If there is voltage is the pump turning?
Pump drive PCB look for burning at top left hand corner.
Pump is it the correct one?
Before the PHE was changed was the hot water slow running?
Unit has been drained, was it sludged up?
If it was it could be the pipes from the unit to the pump and PHE want clearing.
If you look on here home page, list of advertisers.
Or google up one for your area.
The pump does not pump water to the taps. It pumps water from the unit through the PHE which then heats the cold water in thus hot water to taps.
PHE has two parts, the unit / dirty side.
And the DHW side.
Your land lord needs to be dealing with this. Not you!
PC 2000 is one of the easiest ones to work on.
Mike

Thanks Mike.

To answer your questions and add mine to them:
1. Sensors look to be connected correctly though I need to check this with a multimeter or something similar to confirm
2. The pump does run intermittently when a hot tap is turned on though it looks like as the contractor might have possibly put in the pump backwards, as when the pump does run, it seems to be pumping cold water (output to taps pipe is warm to touch before opening a hot tap, goes cold in a few seconds once the pump runs). What direction should the arrow on the pump point when it is fixed (it is pointing downwards currently)? If down is correct, then is there some way that despite that the pump could be fixed in the opposite direction?
3. The pump does not run sometimes even now though, so looks like the original problem is still there
4. What is the correct pump, as in what ratings and details should it have on the top to confirm that it is the correct one?
5. Pump Drive PCB does have a black mark on the extreme left side (whole of the side), not very wide, maybe 2-3mm wide on the whole left side. Does this indicate that the PCB is burnt and hence sometimes works and sometimes does not? Do note that the light flash on the PCB does continue always, though sometimes it is 2 times a sec, sometimes once, sometimes 7-8
6. Unit does not look sludged up as the flow is feels fine whenever the pump works, at least at the moment

Will check the voltage parts that you mention once I get a multimeter or a current detector pen and revert back, but in the meantime if above gives you some info, would be great if you can clarify on my questions above.

Agree the landlord should be looking at this and not me, but he sends his contractor to fix it and just want to make sure that nothing is missed since I'd rather have this resolved quickly.

Thanks a lot.

it sounds to me , there is still a problem with your sensors. ( may incorrect wired in or loose contact), you could test this with connecting the pump to permanent live , if then the water runs ( very, very Hot) on your Taps, there is only 2 options 1st.: one or both sensors faulty ( happens also with new sensors) 2nd.: the pcb faulty ( most events not).
Mario @ Marios Boiler Service
www.marios-boiler-service.co.uk

Thanks Mario. Yes it turned out the PCB was faulty, the contractor replaced it and since then the boiler has been working fine (about 2 weeks now) so hopefully all well now. Cross my fingers :-) Thanks.